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i NITE TA PATENT ()FFICE.

WILLIAM B. PATRICK, OF

MARINE'ITE, WISCONSIN SPECIFICATION forming part of Letters Patent No. 234,142, dated November 9, 1880.

Application filed June "I, 1880. (No model.)

To all whom it may concern Be it known that I, WILLIAM R. PA'rruoK, of Marinette, in the county of Marinette and State of Wisconsin, have invented a certain new and useful Improvement in Processes of Preparing Wood for Making Paper-Pul p, (Case 15;) and I declare that the following is a full, clear, and exact description of the same.

My invention relates to processes of preparing wood for grinding in the manufacture of wood paper-pulp; and it consists in subjecting the wood to the combined action of cold water or water 'of natural temperature admitted through a sprinkling device to the top of the wood and steam admitted to the bottom of the same.

In the specification forming a part of my Letters Patent No. 227,647, dated May 18, 1880, I have described a process of preparing wood for paper-pulp by subjecting it to the combined action of hot water and steam, and have pointed out the advantages of such treatment--viz., shortening the time required for a thorough cleansing of the wood from its impurities and producing a clean white pulp.

I still regard the process described in the said specification as preferable; but if, for any reason, it should be inconvenient, or should not be thought worth while to heat the water before applying it, the same advantages may in considerable measure be attained by the process which I will now proceed to describe pariicularly.

The wood is cut and prepared so as to be in the usual shape for processes of this nature, and is then packed in a tank or chest of suitable construction, which is closed except the tmenings for the admission and steam, as hereinafter described. In the top of the tank, or in any suitable location above the body of the wood, a perforated plate or other suitable sprinkling device is arranged, upon which water, either cold or of any natural temperature, is admitted, and through which it passes in numerousdrops or spray upon the wood below. The perforated plate may form the bottom of a water-pan, or any other construction may be adopted which will serve the purpose I intend, which is to separate the water by passing it through tine openings, so that and outlet of water itcomes minutely divided upon the wood below. At the same time steam is introduced into the tank below the mass of wood by means of suit able steam-pipes entering the bottom of the tank, and having perforations through which the steam may pass outinto the wood. I use, by preference, ordinary live steam; but exhaust-steam will answer the purpose very well.

As the Wateris sprinkled or showered upon the wood it gradually passes through the mass, and is at the same time heated by the steam rising from below, and thus'more effectually saturates and softens the several pieces and washes out all impurities. The steam also operatcs, and more rapidly than the water, to soften the wood and dissolve the resin, acids, 810., which are combined with its fiber. These, when dissolved, are carried downward to the bottom of the tank by the percolating water. At or near the bottom the tank has a suita' ble opening, through which the water charged with the impurities removed from the wood is discharged as freely and rapidly as it flows into the tank. No pressure is required for the introduction'of either the water or the steam, except such as is necessarily attendant upon the admission of steam to the tank. oration should be continued until the wood is thoroughly softened and cleaned, wheu-it is ready for the grinding-machine.

It maybe advisable to provide the tank with a sai'etyvalve to guard against the bad effects of an accidental closing of the discharge-pipes.

What I claim as my invention, and desire to secure by Letters Patent, is-

ln the manufacture of wood paper-pulp, the process hereinabove described for softening and cleansing the wood before grinding the same, consisting in placing the wood in a closed tank and subjecting it to the action of water, admitted cold or of a natural temperature, through a sprinkler, to the top of the mass of wood, in combination with the action of steam admitted tp the bottom of the mass of wood, for the purposes set forth.

WILLIAM 1t. PATRlOK.

Witnesses:

JOHN B/FAIRCHILD, JAMES M. ll'IOORE. 

